[FFmpeg-devel] [PATCH] sdp: Emit only one c= line for multiple streams, if they have the same destination

[Luca Abeni]

Hi Martin,

I'll have a look at this patch later (or tomorrow). Can you provide an
ffmpeg command line generating an SDP that vlc cannot read?
(I never managed to produce such SDPs, and I use ffmpeg to stream
sessions with multiple streams almost dayly).

			Thanks,
				Luca

On Tue, 2010-10-05 at 16:20 +0300, Martin Storsjo wrote:
> VLC/Live555 is unable to play a stream with multiple c= lines.
> ---
>  libavformat/sdp.c |   17 ++++++++++++++++-
>  1 files changed, 16 insertions(+), 1 deletions(-)
> 
> diff --git a/libavformat/sdp.c b/libavformat/sdp.c
> index a4bf7fb..a884d2c 100644
> --- a/libavformat/sdp.c
> +++ b/libavformat/sdp.c
> @@ -466,6 +466,7 @@ int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size)
>      AVMetadataTag *title = av_metadata_get(ac[0]->metadata, "title", NULL, 0);
>      struct sdp_session_level s;
>      int i, j, port, ttl;
> +    int samedest = 0;
>      char dst[32], dst_type[5];
>  
>      memset(buff, 0, size);
> @@ -477,7 +478,19 @@ int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size)
>  
>      port = 0;
>      ttl = 0;
> -    if (n_files == 1) {
> +    if (n_files > 1) {
> +        sdp_get_address(dst, sizeof(dst), &ttl, ac[0]->filename);
> +        samedest = 1;
> +        for (i = 1; i < n_files && samedest; i++) {
> +            char dst_tmp[32];
> +            int ttl_tmp = 0;
> +            sdp_get_address(dst_tmp, sizeof(dst_tmp), &ttl_tmp,
> +                            ac[i]->filename);
> +            if (strcmp(dst_tmp, dst) || ttl_tmp != ttl)
> +                samedest = 0;
> +        }
> +    }
> +    if (n_files == 1 || samedest) {
>          port = sdp_get_address(dst, sizeof(dst), &ttl, ac[0]->filename);
>          resolve_destination(dst, sizeof(dst), dst_type, sizeof(dst_type));
>          if (dst[0]) {
> @@ -497,6 +510,8 @@ int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size)
>          if (n_files != 1) {
>              port = sdp_get_address(dst, sizeof(dst), &ttl, ac[i]->filename);
>              resolve_destination(dst, sizeof(dst), dst_type, sizeof(dst_type));
> +            if (samedest)
> +                dst[0] = 0;
>          }
>          for (j = 0; j < ac[i]->nb_streams; j++) {
>              ff_sdp_write_media(buff, size,